Liquid extracting apparatus



y 5, 1952 o. F. SLABY ETAL LIQUID EXTRACTING APPARATUS Filed Sept. 9,1949 IN VEN TOR.

Patented May 6, 1952 UNITED STATES PATENT OFFICE LIQUID EXTRACTINGAPPARATUS Ollie F. Slaby, Parma, and Le Roy K. Mills, Lyndhurst, OhioApplication September 9, 1949, Serial No. 114,892

1 Claim. 1

Our present invention comprises novel appa ratus for extracting minutelymeasured quantities of fluid. and especially designed for extractingexactly measured minute quantities of blood for use in physiologicalresearches such as the counting of corpuscles and the like.

For the purpose of blood counts it is necessary to puncture the patientand secure a very minute and precisely measured quantity of blood suchas may be contained in a capillary tube; and it is further necessary tosecure this relatively small exact amount of blood rapidly so as toavoid coagulation and without delay dilute such small quantity of bloodwith a suitable diluting fluid and this process must be accomplishedvery rapidly in order to obtain accurate results. In general the processinvolves the puncturing of the patient to obtain 'a drop of blood andthe drawing of a quantity of the blood into a capillary tube exactly toa hair line graduation thereon to give a predetermined exact measure ofa very minute quantity of blood and since the further procedure of theblood count is based on the assumption of an exact and very minutequantity of blood, it is apparent that the blood must not be drawn intothe capillary tube even a hairs breadth off from the measuringgraduation of the capillary tube.

The process of drawing the blood into the capillary tube and thesubsequent dilution of the blood by drawing a diluting fluid into thecapillary tube, also in an exact minute quantity, must necessarily beaccomplished very rapidly in order to avoid coagulation of the blood.Hence, if the exact amounts of fluid are not drawn into the capillarytube initially, the entire operation must be repeated including thepuncturing of the patient to secure a fresh drop of blood, and theinstruments employed are required to be cleaned, sterilized, dried andmade ready for the repetition of the operation which causes delay andannoyance both to the patient and to the practitioner.

l-Ieretofore it has been usual practice to draw the blood and dilutingfluid into the capillary tube, for the purpose as above mentioned, bythe use of a rubber hose attached to the capillary tube,'one end of therubber hose being placed in the mouth of the practitioner and the bloodand diluting fluid being drawn into the capillary tube by mouth suckingaction. By such a process it is very difficult to procure an exactlymeasured amount of fluid of minute quantity as required and it takes agreat deal of skill upon the part of the practitioner to procure a sum-2 ciently close approximation of the exact quantity of fluid desired.For the practitioner who is required to perform this operation onlyoccasionally, it is especially difficult.

It has been heretofore proposed to employ mechanical pumping devices ofthe piston and cylinder types with micrometer screw adjustment for thepurposes of performing such operation, but such devices have not beensuccessful despite their extremely high cost and precision manufacturebecause of the fact that with a piston and cylinder type pumping devicea very small movement of the piston causes too great a movement of bloodinto the capillary tube and the piston and cylinder cannot bemanufactured small enough proportionally to the size of the capillarytube to enable the minute movement of fluid in the capillary tube asrequired.

Moreover, in the manufacture of such piston and cylinder pump devicesthe parts thereof are required to be machined and lapped to very closetolerances at very great expense in order to provide satisfactorypumping action, and even though this type of pumping device is made withthe greatest precision possible, it will not work without thenecessity-for priming each time it is used. The necessity for priming ofthis type of pumping device renders it entirely impractical for use forthe purposes hereof because of the time loss involved and theimpracticability of having conveniently available priming means andpriming fluid. However, the principal objection to piston and cylindertype pump device is that it cannot be made to draw the exact amounts offluid required in the minute quantities necessary for the purposesdescribed.

It is therefore a primary object of the present invention to provideapparatus for the purpose mentioned which will enable exactly measuredminute quantities of fluid to be drawn into a capillary tube with highlyand satisfactorily accurate control for the purpose mentioned and whichapparatus may be readily manipulated with such control by relativelyunskilled persons.

A further object of our invention is to provide apparatus for thepurpose mentioned, having the desired characteristics of capability ofaccurate control, which apparatus may be manufactured at relativelysmall expense as compared with other less satisfactory devices and whichapparatus does not require any machining operation to be performedthereon and does not require any priming in its use.

In carrying our invention into practice, We utilize a flexible,substantially air-tight fluid container, composed preferably of rubberor rubberlike material, and we dispose this flexible container within arigid housing and connect a graduated capillary tube into fluidcommunication with said flexible container; and we further provide screwactuated plunger means engageable with the flexible container within itsrigid housing for depressing or compressing the said flexible containerto express fluid therefrom. We preferably utilize a flexible containerhaving a bulbous or spheroidal shape and we specially form the surfaceof the plunger which contacts with the flexible container with a convexcurvature for non-wrinkling engagement with the flexible fluidcontainer.

For a detailed description of our invention, reference is made to theaccompanying drawing in which:

Figure 1 is a view showing the complete appa ratus of our invention withthe flexible fluid container, its housing, and the plunger head shown insection, and illustrating the flexible fluid container in non-compressedor fully expanded condition.

Figure 2 is a view similar to Figure l but showing the screw actuatedplunger as when moved relative to the housing for action upon theflexibl fluid container to compress it to decrease the internal fluidcapacity thereof.

In the drawings, the fluid extracting apparatus of our invention isdesignated as a whole by the letter A and comprises a substantiallyspheroidal housing, generally designatedby the numeral I, and consistingof two substantially hemispheroidal sections 2 and 3 which are fastenedtogether by suitable fastenings such as the screws 4.

Within the housing I is disposed a flexible and resilient substantiallyair-tight fluid container which, as shown, is of bulbous or spheroidalshape and designated by the numeral 5. The flexible fluid container 5preferably comprises a vacuum bulb composed of rubber or rubber likematerial such as soft rubber and the walls of which are of substantialthickness, as shown, so that the fluid container 5 is highly flexibleand resilient and which normally retains its spheroidal shape, whenundepressed, and after being depressed, when the depressing pressure isreleased, the fluid container 5 rapidly resumes its normal spheroidalshape.

The fluid container or vacuum bulb 5 is provided with a nipple 6 whichextends through an opening in the lower section 3 of the housing to theoutside thereof and provides a passage I for fluid communication betweenthe interior of the container 5 and the exterior of the housing I. Oneend of the capillary pipette or graduated capillary tube 8 is receivedwithin the nipple 6 as shown. The capillary pipette 8 is of usualconstruction and comprises two capillary tubes 9 and I communicatingwith an intermediate mixing chamber II, the capillary tube 6 beingprovided with graduations 8a and the capillary tube In being providedwith graduations Illa. The bulbous mixing chamber I I contains the usualmixing bead I2 which serves to prevent the blood corpuscles fromaggregating when blood is drawn into the capillary pipette 8.

At the upper end of the section 2 of the housing I there is provided athreaded bushing I3 which receives and cooperates with the threads of afine thread screw actuator I4 to the outer end of which is fixed aknurled head I for manipulation of the screw actuator I4 to rotate thesame relatively to the threaded bushing I3 fixed to the section 2 of thehousing. Swiveled to the inner end of the screw I4 within the housing Iis an actuator head or plunger head provided with a convex bulb engagingsurface I6a engageable with the vacuum bulb or flexible container 5 fordepressing or compressing the same and the screw I4 is suitablyactuated.

For the purpose of swivelly connecting the plunger head I6 to the screwI4, the head I6 is counter-bored axially of the screw I4 to receive awasher I'I within the larger diametered portion of the bore, whichwasher I1 is larger than the smaller diametered portion of the bore soas to act as a retainer for the screw I4, the inner end of which isundercut to receive the washer I1 and the end of the screw I4 is thenpeened over the washer to retain it on the screw. The larger diameterportion of the bore is then plugged up with a screw plug I8, the outerend of which is convex and made flush with the convex bulb engagingsurface I'Ba of the plunger head l6.

In the use of the apparatus of our invention, the lower pointed end I9is inserted in a drop of a patients blood while the vacuum bulb orflexible fluid container 5 is in depressed or compressed condition asshown in Figure 2 and then the knurled knob I5 is manipulated to rotatethe screw I4 and move the actuator head I6 upwardly relative to thehousing I to relieve the pressure on the vacuum bulb or fluid container5 permitting atmospheric air pressure to force some of the blood intothe capillary tube 9.

It will be seen that the preliminary actuation of the screw I4 todepress the vacuum bulb or fluid container 5 decreases the internalfluid capacity thereof driving air therefrom and when the screw I4 isactuated in opposite direction to withdraw the plunger I6 and relievethe pressure on the bulb 5, the internal fluid capacity thereof isexpanded allowing more air to enter same thereby permitting the trappedair to expand into the bulb 5 and permit atmospheric air pressure toforce blood up into the capillary tube 9.

It has been found that with the use of a screw I4 having a relativelyfine thread of standard pitch, the movement of the plunger head in itsengagement with the vacuum bulb 5 may be controlled with suflicientaccuracy to allow only slight relief of bulb depressing pressure whenthe screw I4 is backed up such that the movement of fluid up thecapillary tube 9 is relatively slow and can be stopped at the exactpoint desired in said capillary tube or passage 9.

Now, in the use of the apparatus for its intended purpose, the patientsblood will be drawn up into the capillary tube 9 to the lower graduation8a and it must be exactly stopped at that graduation mark as otherwisethe blood count subsequently made will be inaccurate. When the blood isdrawn up to the lower graduation mark 8a, the lower end I 9 of thecapillary pipette is inserted into a diluting fluid and the screw I4again actuated to relieve pressure on the bulb 5 to allow the fluid torise in the pipette to the graduation mark Ifla and again the fluid mustbe stopped exactly at that graduation mark Ifla as otherwise the bloodcount subsequently made will be inaccurate.

The convex curvature of the bulb engaging surface I6a of the plungerhead I6 is such as to cause smooth engagement of the plunger head withthe vacuum bulb 5 in compressed condition, such as shown by Figure 2,whereby to prevent wrinkling of the flexible wall of the vacuum bulb 5so 5 engaged. If the vacuum bulb 5 were wrinkled by engagement with theplunger head IE it would cause spurting or uneven flow of the fluid upthe capillary tube which would result in inaccurate control of suchflow.

From the foregoing it will be seen that our invention provides a verysimple apparatus for the purpose which affords highly accurate controlof the flow of fluid in minute quantities, which apparatus overcomes thedisadvantages of devices previously proposed for this purpose, and ourapparatus being capable of manufacture at relatively small cost comparedwith less satisfactory devices previously in use.

Having thus described our invention, what we claim as new and desire tosecure by Letters Patent of the United States is:

Fluid extracting apparatus of the class described, comprising, incombination, a flexible resilient fluid container of normally generallyspheroidal shape and composed of rubber or like material, a rigidhousing for said fluid container, said housing being of generallyspheroidal shape corresponding to and confining said containertherewithin, said fluid container having a nipple extending through saidhousing, a graduated capillary tube associated with said nipple forfluid communication between said capillary tube and the interior of saidfluid container, and a screw actuated plunger comprising a screwactuator having threaded cooperation with said housing for axialmovement relative thereto upon relative rotation of said actuator, and aplunger head swivelly connected to said actuator and disposed withinsaid housing, said plunger head having a convex engaging surface forengagement with said fluid container to compress the same to decreasethe fluid capacity thereof while closely confined within said housing,said fluid container being resilient to resume its normally spheroidalshape to increase the fluid capacity thereof upon movement of saidplunger to relieve the compressing pressure on said fluid container.

OLLIE F. SLABY.

LE ROY K. MILLS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PAI E N I S Number Name Date 805,743 McConnell Nov. 28,1905 1,447,790 Kovacs Mar. 6, 1923 1,963,886 Chilson June 19, 19342,153,105 Szecsi Apr. 4, 1939 2,166,842 Kagan Jul. 18, 1939 FOREIGNPATENTS Number Country Date 341,511 Great Britain Jan. 14, 1931

